The present invention relates to an image rendering method and apparatus which generate, for example, two-dimensional image information from three-dimensional polygon data, recording media recorded with an image rendering program, and the image rendering program.
In recent years, video game consoles and personal computers continue to see advances in, for example, higher integration and faster speeds of processors, memories, and the like. Accordingly, an image rendering apparatus configured with such a game console or personal computer can generate in real time, from three-dimensional image information, finer, high-definition two-dimensional images rich with diversity and which appear more life-like and give a higher sense of realism, and can render these two-dimensional images upon a two-dimensional screen.
Image rendering, which generates two-dimensional image information from three-dimensional polygon data, is generally comprised of geometry processing and rendering processing. Geometry processing for three-dimensional polygon data comprises geometry processing such as coordinate transformation, clipping and lighting, and perspective projection transformation processing and the like. Rendering processing is a process that generates pixels based upon post-projection transformation processing graphics information (polygon data) and generates two-dimensional image information by determining the color value of each of those pixels.
Incidentally, conventional image rendering apparatus are capable of forming objects by gathering a plurality of polygons. However, a polygon is represented by a multilateral shape in which the node coordinates are each connected by straight lines. As a result, for example, in the case where curved line portions of an object are rendered, the conventional image rendering apparatus approximately expresses the curved line portions by preparing a plurality of small polygons and linking the respective node coordinates that configure the sides of each polygon.
However, the image rendering apparatus when rendering such above-mentioned curved line portions, must process a plurality of polygon data in a short period of time, imposing an extremely heavy load as a result. In addition, the image rendering apparatus that is capable of processing a plurality of polygon data in a short time period needs to be highly efficient and expensive, interfering undesirably with the lowering of costs.